Laminated insecticide dispenser

ABSTRACT

A laminated insecticide dispenser where a central layer contains an insecticide that migrates through the outer layer to the surface of the dispenser. The outer layer also comprises a UV protector which migrates to the surface in order to minimize the UV damage induced on the insecticide.

This application claims the benefit of Danish Application No. 2002 00148filed Jan. 31, 2002 and PCT/DK03/00055 filed Jan. 30, 2003.

FIELD OF THE INVENTION

The present invention relates to a laminiated insecticide dispenser, forexample a three layer tarpaulin.

BACKGROUND OF THE INVENTION

In order to control insects that may be harmful or otherwise undesirableto man, much attention has been directed to improvements in methods fordelivering chemical pest control agents.

A special insecticide dispenser is known from U.S. Pat. No. 4,639,393disclosing a laminated dispenser with two outer wall elements enclosingan inner layer containing a pest controlling agent. The pest controllingagent is able to migrate through the outer layers for a controlledrelease of the agent to the surface of the dispenser. Such a dispensermay be used for example for wall paper, floor coverings or tarpaulins.

It is well known that insecticides when exposed to ultra violet (UVradiation) are degraded through the UV induced chemical reactions. Thedispenser disclosed in U.S. Pat. No. 4,639,393 takes into account UVprotection of the pesticidal agent in the internal reservoir byincorporation of an ultra violet light screening agent in the wallportion of the dispenser.

However, the disclosure in U.S. Pat. No. 4,639,393 does not take intoaccount any protection of the pest controlling agent after migration tothe outer surface of the wall element Especially in tropic regions, UVradiation is very strong and the insecticide that has migrated to thesurface of the laminate may disintegrate at a rate so high that noefficient insecticidal effect may be achieved. Therefore, the laminateddispenser disclosed in the above mentioned patent is primarily suitedfor indoor use or generally where high levels of UV radiation isavoided. In connection with applications where a high intensity of UVradiation is given, the insecticide release from a dispenser asdisclosed in U.S. Pat. No. 4,639,393 has to be fast such that a suitableactive level of insecticide, or alternatively an insect attractant, canbe maintained on the surface. However, this limits the lifetime of thedispenser, because the insecticide reservoir is emptied after relativelyshort time, for example a few weeks.

It is the purpose of the invention to improve existing dispensers suchthat they are more suitable for application in outdoor environmentswhere the dispenser is exposed to primarily high level UV radiation.

DESCRIPTION OF THE INVENTION

This purpose is achieved with a laminated insecticide dispensercomprising a first outer solid, non porous polymeric wall element withone side facing the environment of said dispenser and constituting afirst surface of the dispenser, a second outer wall element with oneside facing the environment of the dispenser and constituting a secondsurface of the dispenser, and at least one inner layer between the firstand the second wall element. The inner layer comprises at least onepesticidal agent being capable of migration through the first outer wallelement. The first outer wall element contains a UV protecting agent toreduce the UV radiation induced degradation of the pesticidal agent whenthe pesticidal agent is exposed to UV radiation. According to theinvention, this UV protecting agent is capable of migrating through thefirst outer wall element for reaching the first surface.

The UV protective agent used in connection with the invention is capableof reducing the UV radiation induced degradation of the pesticidalsubstance, also when this pesticidal substance is on the first surfaceof the dispenser, such that the pesticidal substance may be optimallyefficient as long as possible. Due to the reduced degradation of thepesticidal substance on the surface of the dispenser, a relatively smallamount of pesticidal substance has to be supplied to the surface bymigration through the outer wall element. Thus, by having a UVprotecting agent supplied to the dispenser surface, the amount of usedpesticides is reduced and the life time of the laminated insecticidedispenser according to the invention is prolonged as compared tolaminated dispensers according to prior art.

The first outer wall element is constructed such that the migrationspeed of the pesticidal substance is fast enough to ensure an effectivelevel of the pesticidal substance on the outer surface of the dispenseraccording to the invention. On the other hand, in order to avoid overshooting of the necessary effective level of the pesticidal substance,the migration rate through the first outer wall element may becontrolled by migration moderation. Such moderation may be achieved bythe physical properties of the outer wall element, for example thedensity or the thickness. However, the migration rate for the pesticidalsubstance may also be controlled by migration inhibitors on the innersurface of the first outer wall element or inside the first outer wallelement.

In principle, the migration to the surface of the dispenser may also bereduced by a migration inhibitor on the surface of the dispenser.However, in this case, a large amount of the migrated pesticidal agentmay accumulate on the inside of the wall element just below themigration inhibitor on the surface, which is inconvenient, as the UVintensity at this location is stronger than at the reservoir locationinside the dispenser. Therefore this solution—though possible—is notpreferred in connection with the invention. A better option is to havethe migration inhibition layer on the inner side of the wall element orthroughout the wall element. Hereby, the release rate from the innerlayer to the surface becomes independent on the concentration in theinner layer, a so-called first order release rate, and becomes constantover long time.

Usable migration inhibitor are for example triazine derivatives, whichat the same time have a fire resisting effect.

When a dispenser according to the invention is used immediately afterproduction, some time may pass before the pesticide has migrated to thesurface from the inner layer. In order to avoid a long initial periodwith a too low concentration of insecticide on the surface of thedispenser, pesticide may also be incorporated in the first outer wallelement or even be disposed on the surface from the beginning. Such aninitial application to the surface may be achieved, for example, byspraying on the surface.

A dispenser according to the invention may in a further development beconstructed such that the release of the insecticide or the UVprotecting agent or both is temperature dependent in a predeterminedway. For example, if the dispenser is to be used in tropic regions, arelatively high temperature can be expected, when the dispenser isexposed to sun light. In contrast, the temperature during storage andtransport is usually much lower. This fact can be utilized by atemperature dependent migration speed such that the relatively lowtemperature during storage and transportation results in a slowmigration or even negligible migration of the UV protecting agent and/orthe insecticide—allowing a long term storage of the dispenser accordingto the invention—whereas the migration speed is increased when thedispenser is exposed to sunlight or high temperature.

A temperature dependent release of the UV protecting agent isadvantageous in tropical regions because extensive exposure to sunlightwith corresponding heating of the dispenser also increases the need fora relatively high amount of UV protecting agent. This way, the dispenseraccording to the invention functions as a self-regulating dispenser of aUV protecting agent.

The migration rate of the UV protecting agent through the first outerwall element may as well be controlled by the physical properties of thesheet or by applying a migration inhibitor in the first outer wallelement, where the inhibitor is directed towards a control of themigration rate of the UV protecting agent. This migration inhibitor mayoptionally function in dependency of the temperature of the dispenser.

The UV protecting agent is preferably incorporated in the first outerwall element, because it, this way, yields an efficient UV protection ofthe pesticide reservoir. Also, typically the migration speed is lowerfor UV protecting agents than for pesticidal agents, why the UVprotecting agent preferably is located nearer to the dispenser surfacefrom the beginning than the pesticidal agent itself, for example in theouter layer. In case that the migration speed of the UV protecting agentthrough the outer wall element is fast enough for the desired effect,the UV protecting agent may be supplied to the first outer sheet from areservoir comprised by the inner layer.

By applying different migration inhibitors, where one inhibitor or onegroup of inhibitors are acting on the pesticidal substance and anotherinhibitor or group of inhibitors may act on the UV protecting agent,optimized migration rates may be achieved such that a perfectly matchresults between the amount of UV protecting agent and the pesticidalagent on the surface of the laminated insecticide dispenser according tothe invention.

In case that the pesticidal agent according to the invention is amixture of a number of pesticidal substances, different migrationinhibitors may be applied, where each inhibitor is directed towards ratemigration control of at least one of the substances. Also, theinsecticides by themselves will have different migration rates, and thiscan be exploited for a successive release of insecticides. Equivalently,in case that the UV protecting agent consists of a number of UVprotection substances, a number of special migration rate reducinginhibitors may be applied for controlling the migration rate of theindividual UV protecting substances. As above, the different migrationrates of different UV filters or other types of protecting substancescan be used to match with insecticides with different absorption spectraor to obtain a prolonged UV protection by combining fast and slowmigrating filters. The different types of migration inhibitors may bechosen with substantial temperature dependence matching certainappliances, for example use in tropical regions with strong exposure tosunlight.

Thus, it is possible according to the invention to achieve an optimumamount of different pesticidal substances on the surface of thedispenser and at the same time achieve an optimum amount of UVprotection substances on the surface of the dispenser such that theinsecticides may act as efficient as possible and for at time as long aspossible. Dispensers according to the invention are intended to workefficiently for years.

A long lasting dispenser according to the invention is especiallysuitable for refugee camps in warm countries because the financial aidoften is limited and irregular. Therefore, once a dispenser, for exampleas part of a tent, has been financed and delivered, the functioning ofthis dispenser should be as long as possible. The ready-to-use tent ortarpaulin further has the advantage that other insecticide handling inthe camp is much reduced or avoided.

Possible migration inhibitors are metallic salts like bromides, whichalso may have some fire retardation effects. Substances as Carbon Blackmay be used as well, where Carbon Black has the additional property ofbeing a UV protector. Substances as kaolin, stearates and migrating UVfilters may, on the other hand, be used for increasing migration.

Optimization of the insect combating properties of the dispenser isfurthermore achieved by matching the UV protecting agent or agents tothe pesticidal agent in that the wavelength range for the most effectiveUV filter properties of the protecting agent overlaps with thosewavelengths, where the pesticide is most sensitive for disintegration.

In order to prevent the polymer in the dispenser from UV induceddisintegration, the different layers in the dispenser may containadditional UV protectors, for example Carbon Black, as far as themigrating UV protecting agent is not sufficiently effective.

Furthermore, the outer sheet layers and the inner layer may additionallycontain HALS molecules. HALS is an abbreviation for Hindered Amine LightStabilizers, which is a group of additives having a common chemicalstructure (a piperidine ring) as part of their molecule. These highlyeffective UV stabilizers protect the polymer by scavenging free radicalsthat may occur due to UV irradiation. The effect of Hals molecules isalso beneficially on the UV protecting agent as it prolongs the lifetimeof this agent.

The second outer wall element may be of the same kind as the first outerwall element and exhibit analogue properties for a likewise function.However, the second outer wall element may alternatively be of adifferent kind, for example it may be an element which completely blocksany migration of pesticides or UV protecting agents. An example of ablocking wall element is a metal foil.

Alternatively, the second outer wall element may be constructed suchthat it prevents the UV protecting agent to migrate through it, butpermits the pesticidal agent to migrate through. The latter embodiment,may be used in cases where the dispenser is only exposed to UV radiationon the first side of the dispenser. This would for example be the case,if the laminated dispenser according to the invention is used as a roofor a tent, where the outer side, namely the first side of the dispenseris exposed to UV radiation, while the second side—for example beinginside the tent—is not exposed to UV radiation. The total blocking ofthe migration of the UV protecting agent through the second outer wallelement implies that only part of the amount of the UV protecting agentis necessary in such a dispenser as compared with a dispenser where thefirst and the second outer wall elements allow migration of the UVprotecting agent, for example by being identical.

The second outer wall element may be different from the first outer wallelement in that only some special pesticidal substances migrate throughthe first outer wall element, while other special pesticidal substancesmigrate through the second outer wall element. Likewise may apply fordifferent UV protecting substances. This would be useful in case that adispenser according to the invention is set up with one side facing themorning sun and the other side facing the evening sun. Insects that areactive in the morning may set on the warm side of the dispenser, whichis facing the morning sun, while other insects may be touching the otherside of the dispenser which is facing the evening sun. For those insectsthat are active in the morning as compared to those that are active inthe evening, different insecticides may be necessary, why a selectivemigration of pesticidal substances towards the first or the second sideof the dispenser would be highly useful. Analogue arguments apply forthe UV protecting substances that are related to the differentpesticidal substances. Also, such considerations are advantageous, ifthe dispenser according to the invention is used as a tent, whereinsects inside the shady tent may primarily be of a different kind thaninsects on the sunny and warm outside surface of the tent.

The case that only some specific pesticides migrate through the firstouter wall element while others migrate through the second outer elementmay be utilized for combat of insects that may readily become resistantto pesticides. If an insect has become resistant to the pesticide on onesurface of the dispenser, there may still be a high chance of lethaleffect on this insect from the pesticide on the other surface.

The migration speed of the different agents or substances may beregulated by physical properties as density and thickness of the outerwall elements as described above. Alternatively, the migration rate maybe regulated through inclusion of different kinds of migration filtersbetween the outer wall elements and the inner layer or by constructingan inner layer consisting of a compound structure of different innerwall elements and migration filters. Furthermore, the inner layers orouter wall elements may have different thickness and different migrationrates for different pesticidal agent or UV protecting agents. Thus byarranging a suitable number of different inner layers and outer wallelements with different thickness, densities, applied migration filters,and chemical migration inhibitors and migration reducers, almost anydesired combination of pesticidal agents and UV protecting agents arepossible to obtain at the first and the second surface of the dispenser.

A number of substances used in an applicable pesticidal agents arementioned in the following together with UV protecting agents.

The present invention relates to but is not limited to the followingactive insecticides selected from the group comprising pyrethroidcompounds such as

-   -   Etofenprox: 2-(4-ethoxyphenyl)-2-methylpropyl-3-phenoxybenzyl        ether,    -   Fenvalerate:        (RS)-alpha-cyano-3-phenoxybenzyl(RS)-2-(4-chlorophenyl)-3methylbutyrate,    -   Esfenvalerate:        (S)-alpha-cyano-3-phenoxybenzyl(S)-2-(4-chlorophenyl)-3-methylbutyrate,    -   Fenpropathrin: (RS)-alpha-cyano-3-phenoxybenzyl        2,2,3,3-tetramethylcyclopropanecarboxylate,    -   Cypermethrin: (RS)-alpha-cyano-3-phenoxybenzyl (1RS)-cis,        trans-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropanecarboxylate,        and isomer variants as alfa- and beta-cypermethrin,    -   Permethrin: 3-phenoxybenzyl        (1RS)-cis,trans-3-(2,2-dichlorovinyl)-2,2-dimethyl-cyclopropanecarboxylate,    -   Cyhalothrin: (RS)-alpha-cyano-3-phenoxybenzyl        (Z)-(1RS)-cis-3-(2-chloro-3,3,3-trifluoroprop-1-enyl)-2,2-dimethylcyclopro        panecarboxylate, and isomer variants as lambda-cyhalothrin,    -   Deltamethrin: (S)-alpha-cyano-3-phenoxybenzyl        (1R)-cis-3-(2,2-dibromovinyl)-2,2-dimethylcyclopropanecarboxylate,    -   Cycloprothrin: (RS)-alpha-cyano-3-phenoxybenzyl        (RS)-2,2-dichloro-1-(4-ethoxyphenyl)cyclopropanecarboxylate,    -   Fluvalinate (alpha-cyano-3-phenoxybenzyl        N-(2-chloro-alpha,alpha,alpha-trifluoro-p-tolyl)-D-valinate),    -   Bifenthrin:        (2-methylbiphenyl-3-ylmethyl)0(Z)-(1RS)-cis-3-(2-chloro-3,3,3-trifluoro-1-propenyl)-2,2-dimethylcyclopropanecarboxylate,    -   2-methyl-2-(4-bromodifluoromethoxyphenyl)propyl    -   (3-phenoxybenzyl) ether,    -   Silafluofen: 4-ethoxyphenyl        (3-(4-fluoro-3-phenoxyphenyl)propyl}dimethylsilane,    -   D-fenothrin: 3-phenoxybenzyl (1R)-cis,trans)-chrysanthernate,    -   Cyphenothrin: (RS)-alpha-cyano-3-phenoxybenzyl (1R-cis,        trans)-chrysanthemate, D-resmethrin: 5-benzyl-3-firylmethyl        (1R-cis,trans)-chrysanthemate,    -   Acrinathrin: (S)-alpha-cyano-3-phenoxybenzyl        (1R-cis(Z))-(2,2-dimethyl-3-(oxo-3-(1,1,1,3,3,3-hexafluoropropyloxy)propenyl(cyclopropanecarboxylate,    -   Cyfluthrin: (RS)-alpha-cyano-4-fluoro-3-phenoxybenzyl        3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropanecarboxylate,    -   Tefluthrin: 2,3,5,6-tetrafluoro-4-methylbenzyl (1RS-cis        (Z))-3-(2-chloro-3,3,3-trifluoroprop-1-enyl)-2,2-dimethylcyclopropanecarbo        xylate,    -   Transfluthrin: 2,3,5,6-tetrafluorobenzyl        (1R-trans)-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropanecarboxylate,    -   Tetramethrin: 3,4,5,6-tetrahydrophthalimidomethyl (1RS)-cis,        trans-chrysanthemate,    -   Allethrin: (RS)-3-allyl-2-methyl-4-oxocyclopent-2-enyl        (1RS)-cis, trans-chrysanthemate,    -   Prallethrin: (S)-2-methyl-4-oxo-3-(2-propynyl)cyclopent-2-enyl        (1R)-cis, trans-chrysanthemate,    -   Empenthrin: (RS)-1-ethynyl-2-methyl-2-pentenyl        (1R)-cis,trans-chrysanthemate,    -   Imiprothrin: 2,5-dioxo-3-(prop-2-ynyl)imidazolidin-1-ylmethyl        (1R)-cis,        trans-2,2-dimethyl-3-(2-methyl-1-propenyl)-cyclopropanecarboxylate,    -   D-flamethrin: 5-(2-propynyl)-furfuryl        (1R)-cis,trans-chrysanthemate, and 5-(2-propynyl)furfuryl        2,2,3,3-tetramethylcyclopropanecarboxylate;        other active insecticides that may be used alone or in        combination, but preferably not mixed with pyrethroids, are e.g.        carbamate compounds such as    -   Alanycarb:        S-methyl-N[[N-methyl-N-[N-benzyl-N(2-ethoxy-carbonylethyl)aminothio]carbamoyl]thioacetimidate,    -   Bendiocarb: 2,2-dimethyl-1,3-benzodioxol-4yl-methylcarbamate),    -   Carbaryl (1-naphthyl N-methylcarbamate,    -   Isoprocarb: 2-(1-methylethyl)phenyl methylcarbamate,    -   Carbosulfan:        2,3dihydro-2,2-dimethyl-7-benzofuranyl[(dibutylamino)thio]methylcarbamate,    -   Fenoxycarb: Ethyl[2-(4-phenoxyphenoxy)ethyl]carbamate,    -   Indoxacarb:        Methyl-7-chloro-2,3,4a,5-tetrahydro-2-[methoxycarbonyl        (-4-trifluoromethoxyphenyl)]    -   Propoxur: 2-isopropyloxyphenol methylcarbamate,    -   Pirimicarb:        2-dimethylamino-5,6-dimethyl-4-pyrimidinyl-dimethylcarbamate,    -   Thidiocarb: Dimethyl    -   N,N′(thiobis((methylimino)carbonoyloxy)bisethanimidiothioate),    -   Methomyl: S-methyl N-((methylcarbamoyl)oxy)thioacetamidate,    -   Ethiofencarb: 2-((ethylthio)methyl)phenyl methylcarbamate,    -   Fenothiocarb: S-(4-phenoxybutyl)-N,N-dimethyl thiocarbamate,    -   Cartap:        S,S′-(2-5dimethylamino)trimethylene)bis(thiocarbamate)hydrochloride,    -   Fenobucarb: 2-sec-butylphenylmethyl        carbamate,3,5-dimethylphenyl-methyl carbamate,    -   Xylylcarb: 3,4-dimethylphenylmethylcarbamate;        additionally, active insecticides such as organophosphorous        compounds may be applied in accordance with the invention        including compounds such as    -   Fenitrothion: O,O-dimethyl 0-(4-nitro-m-tolyl)phosphorothioate,    -   Diazinon:        0,0-diethyl-0-(2-isopropyl-6-methyl-4-pyrimidinyl)phosphorothioate,    -   Pyridaphenthion: 0-(1,6-dihydro-6-oxo-1-phenylpyrazidin-3-yl)        0,0-diethyl phosphorothioate,    -   Pirimiphos-Etyl: 0,0-diethyl        0-(2-(diethylamino)-6-methyl-pyrimidinyl)phosphorothioate,    -   Pirimiphos-Methyl:        0-[2-(diethylamino)-6-methyl-4pyrimidinyl]0,0-dimethyl        phosphorothioate,    -   Etrimphos:        0-6-ethoxy-2-ethyl-pyrimidin-4-yl-0,0-dimethyl-phosphorothioate,    -   Fenthion: 0,0-dimethyl-0-[-3-methyl-4(methylthio)phenyl        phosphorothioate,    -   Phoxim: 2-(diethoxyphosphinothoyloxyimino)-2-phenylacetonitrile,    -   Chlorpyrifos:        0,0-diethyl-0-(3,5,6-trichloro-2-pyrinyl)phosphorothioate,    -   Chlorpyriphos-methyl: 0,0-dimethyl        0-(3,5,6-trichloro-2-pyridinyl)phosphorothioate,    -   Cyanophos: 0,0-dimethyl 0-(4cyanophenyl)phosphorothioate,    -   Pyraclofos:        (R,S)[4chlorophenyl)-pyrazol-4-yl]-0-ethyl-S-n-propyl        phosphorothioate, Acephate: 0,S-dimethyl        acetylphosphoroamidothioate,    -   Azamethiphos: S-(6-chloro-2,3-dihydro-oxo-1,3-oxazolo        [4,5-b]pyridin-3-ylmethyl phosphorothioate,    -   Malathion: 0,0-dimethyl phosphorodithioate ester of diethyl        mercaptosuccinate,    -   Temephos: (0,0′(thiodi-4-1-phenylene) 0,0,0,0-tetramethyl        phosphorodithioate,    -   Dimethoate: ((0,0-dimethyl        S-(n-methylcarbamoylmethyl)phosphorodithioate,    -   Formothion: S[2-formylmethylamino]-2-oxoethyl]-O,O-dimethyl        phosphorodithioate,    -   Phenthoate: 0,0-dimethyl        S-(alpha-ethoxycarbonylbenzyl)-phosphorodithioate;        in addition, especially for ticks and mites, the following        insecticides and acaricides may be applied:    -   Neonicotioids as Acetamidiprid and Imidacloprid:        -   1 -(6-chloro-3-pyridylmethyl)-N-nitro-2-imidazolidinimine;    -   Pyridins as Pyriproxyfen:        2-[1-+methyl-2-(4-phenoxyphenoxy)ethoxyy]pyridine;    -   Pyrimidines as Pyremidifen        -   5-chloro-N-(2,-[4-(2-ethoxyethyl)-2,3-dimethyl-phenoxy]-ethyl)6-ethylpyrimid            in-4-amin    -   Quinazoline as Fenazaquin: 4-[[-(1,1-dimethylethyl)phenyl,        pyrazoler and phenyl    -   Pyrazoles as Dihydropyrazole, Fipronile, Tebufenpyrad, and        Fenpyroproximate:        -   1,1-dimethylethyl-4-[[[[(1,3-dimethyl-5-phenoxy-1H-pyrazol-4-yl)-methylene]ammo]oxy]methyl]benzoate]    -   Pyrazoner as Tebufenpyrad,    -   Carbonitrils as Vaniliprol,    -   Hydrazins as Tebufenozide,    -   Hydrazons,    -   Azomethins,    -   Diphenyls as Bifenazate;        furthermore active insecticides with a sterilising effect on        adult mosquitoes and/or with a growth regulating effect may        applied such as:    -   (alfa-4-(chloro-alpha-cyclopropylbenzylidenamino-oxy)-p-tolyl)-3-(2,6-diflourobenzoyl)urea,    -   Diflubenzuron:        N-(((3,5-dichloro-4-(1,1,2,2-tetraflouroethoxy)phenylamino)carbonyl)2,6        diflouro benzamid,    -   Triflumuron:        2-Chloro-N-(((4-(triflouromethoxy)phenyl)-amino-)carbonyl)benzamide,        or    -   a triazin such as N-cyclopropyl-1,3,5-triazine-2,4,6-triamin.

Other possible agents are mentioned in U.S. Pat. No. 4,639,393.

The insecticidal agent may also contain an insect repellant, for examplefor repellant of certain predetermined insects.

The repellant is at least one from the group consisting of

-   -   N,N-Diethyl-meta-toluamide(DEET),    -   N,N-diethylphenylacetamide (DEPA),    -   1-(3-cyclohexen-1-yl-carbonyl)-2-methylpiperine,    -   (2-hydroxymethylcyclohexyl)acetic acid lactone,    -   (2-ethyl-1,3-hexandiol), indalone,    -   Methylneodecanamide (MNDA),    -   a pyrethroid not used for insect control such as        (±)-3-allyl-2-methyl-oxocylopent-2-(+)enyl-(+)trans-chrysantemate(Esbiothrin),    -   a repellant derived from or identical with plant extracts like        limonen, citronella, eugenol, (+)-Eucamalol (1),        (−)-1-epi-eucamalol or crude plant extracts from plants like        Eucalyptus maculata, Vitex rotundifolia, Cymbopogan martinii,        Cymbopogan citratus (lemon grass), Cymopogan nartdus        (citronella).

Instead of a repellent, a pest attractant may be used for attractingcertain insects, for example certain pheromones. This way, the dispensermay be used for selective combat of specific species. For example somecertain insects may be repelled while others may be attracted.

Also incorporated in the first and/or second outer wall element, or inthe inner layer with migration through the outer wall elements, may beso called chemical arrestants. These are chemical substances that workthrough contact with insects such that insects stay longer at theexposed surface of the dispenser than they else would do. The longerstay of the insect on the surface of the dispenser may result in a moreefficient combat with a higher kill rate. In order to preventdisintegration of the chemical arrestant, UV protecting agents may beemployed for this as well.

Interesting as a UV protecting agent are Benzophenon-derivatives, forexample the agent known under the commercial name Chimassorb 81,comprising the chemical substanceMethanone,2-hydroxy4-(octyloxy)-phenyl. Chimassorb 81 is a UV protectingagent having an absorption in that part of the radiation spectrum, wheredeltamethrin and other pyrethroids absorb UV energy and get unstable.Because the molecules of Chimassorb 81 are rather small, it easily candiffuse through polyethylene, where polyethylene is a suitable polymerfor the outer wall elements of the dispenser and optionally also for theinner layer. The diffusion ability for Chimassorb 81 through polymer isopposite to most others UV protecting agents, for which the diffusionspeed is extremely low, especially those UV protecting substances thatare used for UV protection of polyethylene.

Another suitable UV protecting agent is available from Ciba Geigy andknown by the commercial name Tinuvin 326 containing the chemicalsubstance with the name Phenol,2-(5-chloro-2H-benzotriazole-2-yl)-6-(1,1-dimethyl)-4-methyl. Tinuvin326 may be used for protection of polyethylene in which it does notmigrate.

Chimasorb 81 as well as Tinuvin 326 have been observed to have amigration promoting effect.

Advantageously, Tinuvin 326 may be used in combination with Chimassorb81. This has been demonstrated in an experiment, where the content ofdeltamethrin in a wall element was measured after UV radiation exposure.The measured results are shown in the table below.

amount left amount left agent - start amount 1.3 after 16 hours after 24hours none 0.34 0.18 Chimasorb 81 0.89 0.71 Tinuvin 326 0.44 0.40Tinuvin 326 + Chimasorb 81 1.03 0.87

The initial amount in the wall element was 1.3 g deltamethrin per kgwall element. It is clearly seen from the data in the table that acombination is an advantage as the amount of deltamethrin left after 24hours is almost five times higher than without UV protecting agent.

Another suitable radical scavenger that may be used in connection withthe invention is known under the commercial name Tinuvin 494™ availablefrom Ciba Geigy®. It contains the high molecular stabilizer also knownunder the commercial name Chimasorb 119FL™. It contains1,3,5-Triazine-2,4,6-triamin,N,N′″[1,2-ethane-diyl-bis,{[[4,6-bis[butyl(1,2,2,6,6-pentamethyl-4-piperidinyl]1-3,5-triazine-2-yl]imino]-3,1-propranediyl]}-bis[N′,N″-dibutyl-N′,N″-bis(1,2,2,6,6-pentamethyl-4-piperidinyl).

For most applications, the laminated dispenser according to theinvention will be of flexible type for use as tents, shelters,tarpaulins, floor coverings or wall coverings. However, it is alsopossible that a laminate dispenser according to the invention is of therigid type.

The inner layer may be a polymeric wall element of the porous andunporous type, but it may also be fabric or paper material that issoaked with a gel or a liquid. Alternatively, the inner layer may simplyconsist of a gel that is disposed between the outer wall elements.

A suitable material for the wall elements and the inner layer ispolyethylene. However, as the extrusion temperature when producingpolyethylene structures is so high that contained insecticides maydisintegrate if contained in the structure. Therefore for certainpesticidal agents, PVC (poly vinyl chloride) may be preferred with anextrusion temperature of only 80-100° C. Further alternatives are forexample nylon and soft polystyrene. The polyethylene may also containEVA (ethyene-co-vinylacetate) and thus obtain a higher migration ratesand a softer product.

A dispenser according to the invention may in addition comprise othersubstances that are useful in dependence of the actual application. Forexample, the dispenser according to the invention may in additiondispense smelling substances such that the dispenser or the regionaround the dispenser has an intended smell, for example a smell with arefreshing effect to human beings as peppermint oil, lemon oil or teatree oil, or a smell which repels certain animals, for example tea treeoil for repelling fleas. This may be of advantage when a dispenseraccording to the invention is used as tarpaulin, for example inconnection with tents for life aid or field hospitals. In this case, itmay in addition be of advantage to use other substances, that may beused for repelling larger animals, for example cats or dogs or otherkinds of predators—such kinds of substances are widespread commerciallyavailable in liquid form. For example, repellents to repel cats mayinclude allyl isothiocyanate (oil of mustard), amyl acetate, anethole,capsaicin, cinnemaldehyde, citral, citronella, citrus oil, eucalyptusoil, geranium oil, lavender oil, lemongrass oil, menthol, methyl nonylketone, methyl salicylate, naphthalene, nicotine, paradichlorobenzeneand thymol. A number of these substances are known to have refreshingeffects on humans and pain relieving effect.

Other releasable substances from the dispenser according to theinvention may be agents that have a medical effect, for exampleevaporating euphoriant or pain reducing substances, for example drugs,to be used in connection with wall elements, for example tents, aroundhumans that are suffering of pain or different kinds of illness. Suchkind of application may be considered in connection with warfare orduring life aid in regions with catastrophes.

Another application of a dispenser according to the invention is as adirect cover to resting humans, where the dispenser may prevent nuisancedue to insect attack. In this case, it can be of advantage if only thefirst surface of the dispenser facing away from the body is dispensingan insecticide, eventually in combination with an insect repellant.Optionally, the second surface, facing the human body may be dispensinga medical drug or a smelling agent as described above. A suitablesmelling agent may be based on ethereal oils. Ethereal oils are known tohave pain relieving and/or refreshing effects, for example orange oil,basil oil and peppermint oil.

As a further application, a dispenser according to the invention mayform part of a wound cover, where the first surface forms the outer sideof the wound cover and dispenses a pesticide, preferably with an insectrepellant, and thus reduces the danger of infections due to insects,which is of pronounced risk in tropical countries. Facing the wound, thesecond surface of the dispenser may release a substance promoting thehealing of the wound, for example including a bactericide andantioxidants. In this connection, it should be mentioned that tea treeoil is known to have antibacterial and fungicidal properties in additionto insect repelling effects.

SHORT DESCRIPTION OF THE DRAWING

The invention will be explained in more detail in the following withreference to the drawings, where

FIG. 1 is a schematic of a dispenser according to the invention,

FIG. 2 is a schematic of a compound dispenser structure.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 a shows a dispenser 1 according to the invention having a firstouter solid, non porous polymeric sheet 2 constituting a first surface 3of the dispenser 1. The dispenser penser 1 also has a second outer wallelement 4 with one side constituting a second surface 5 of the dispenser1. Between the first 2 and the second 4 outer wall element, an innerlayer 6 is located. The thickness of the wall elements 2, 4 and theinner layer 6 may be mutually different, for example in dependence ofthe desired physical properties and functions.

Though shown as a flat sheet in FIG. 1 a, the dispenser 1 according tothe invention may as well have different shapes, for example bent,twisted, elliptical or round as shown in FIG. 1 b. In case that thefirst 2 and the second 4 wall element are identical for the shown roundembodiment, the inner layer 6 may in practice be surrounded by only onewall element substituting the first 2 and the second wall element 4.

In case that a dispenser as shown in FIG. 1 b is fabricated with a smalldiameter, it may be used as a fiber that can be woven into other morecomplex structures, for example fabrics for clothes, or net structures.

The materials for the dispenser wall elements and the inner layer may bepolyethylene, for example of low density type for the wall elements andof high density type for the inner layer. Also PVC may be used.

When using a dispenser according to the invention against mosquitoes,deltamethrin may be used as one of the migrating pesticidal agents.Different doses in the wall elements and the inner layer may be appliedaccording to the preferred properties. In the following a few examplesare given for possible doses, the doses, however, in no way beinglimiting the general aspects of the invention.

The surface dose of deltamethrin may be between 15 mg/m² and 150 mg/m²,for example 100 mg/m². Experiments have shown that a dose of 1 g ofdeltamethrin per kg wall element can be used in an outer polyethylenewall element when the thickness of the wall element is 0.05 mm. The dosein the inner layer, which supplies the pesticidal agent to a low densitypolyethylene wall element for migration, is for example 6 g/kg when thethickness of the wall element is 0.1 mm.

As compared to deltamethrin, the necessary dose for etofenprox andpermethrin is an order of magnitude higher, while the dose for malathionis about 20 times higher.

For a cylindrical dispenser as shown in FIG 1 b, when used as arelatively thin fiber, the migration distance from the inner layer 6 tothe surface 3 of the dispenser 1 is relatively short and the dose ofmigrating deltamethrin in the wall element 2, 4, may be chosen to forexample 50 mg/m². This dose is dependent on the migration speed, whichmay be regulated with migration inhibitors in relation to the dose inthe inner layer 6 which provides the insecticide for migration throughthe outer wall element 2,4.

For polyethylene, the content of pesticides normally is below 10% of theweight of polyethylene itself, as the pesticides influences the physicalproperties of the polyethylene for higher doses.

In FIG. 2, an alternative embodiment is shown, where in addition to thefirst 2 and the second 4 outer wall elements and the inner layer 6, alsoadditional layers 7, 8 are incorporated in the dispenser 1. Theseadditional layers 7, 8 may serve different purposes for the functioningof the dispenser 1.

For example, one additional layer 7 may separate the inner layer 2 froma further inner layer 8 such that the inner layer 6 feeds the firstouter wall element 2 with one insecticide while the further inner layer8 feeds the second outer wall element 4 with a different insecticide, areleasable medical drug, a smelling agent, or some other of theaforementioned substances. In order not to mix the substances in theinner layer 6 and further inner layer 8, they are separated by theseparating additional layer 7.

The separating additional layer 7 may also be constructed such thatcertain substances are diffusing through the layer, while others arenot. By choosing a multi layer principle with different thickness anddiffusion/migration properties, a large variety of insecticides and UVprotectors may be controlled with respect to the migration speed andwith respect to which surface 3, 5 the insecticides are migrating to.

Apart from application as fibers in woven or non-woven structures, forexample fabrics or nettings, and as tarpaulin or tents as describedabove, a dispenser according to the invention may be used for collarsfor animals, for example dogs and cats, or for ear tags on animals, forexample cattle.

Furthermore, a dispenser according to the invention may be used as partof a building construction in order to prevent termite attack, forexample as a covering of walls.

1. A laminated insecticide dispenser comprising a first outer solid, nonporous polymeric wall element with one side facing the environment ofsaid dispenser and constituting a first surface of said dispenser,optionally a second outer wall element with one side facing theenvironment of said dispenser and constituting a second surface of saiddispenser, at least one inner layer between said first and second outerwall element or at least one inner layer surrounded by the first layer,said inner layer comprising at least one pesticidal agent being capableof migration through said first outer wall element, said first outerwall element containing a UV protecting agent, where said UV protectingagent reduces the UV radiation induced degradation of said pesticidalagent when said pesticidal agent is exposed to UV radiation wherein saidUV protecting agent is capable of migrating through said first outerwall element for reaching said first surface and wherein the migrationspeed of the UV protecting agent is fast enough to ensure UV protectionon the first surface.
 2. A laminated insecticide dispenser according toclaim 1, wherein said first outer wall element comprises a migrationinhibitor for reducing the migration speed of the pesticidal agent tothe first surface of the dispenser.
 3. A laminated insecticide dispenseraccording to claim 1, wherein said inner layer is at least one from thegroup consisting of a porous or non-porous polymeric wall element, a gelsoaked or liquids soaked fabric, a gel soaked or liquids soaked papermaterial, a gel.
 4. A laminated insecticide dispenser according to claim1, wherein said inner layer constitutes a reservoir for at least one UVprotecting agent capable of migrating through said first outer wallelement and optionally through said second outer wall element.
 5. Alaminated insecticide dispenser according to claim 1, wherein saidsecond outer wall element is at least one from the group consisting of awall element identical to said first wall element, a wall elementblocking the migration of the pesticidal agent, a wall element blockingthe migration of the UV protecting agent, a non porous polymeric sheet,a metal foil.
 6. A laminated insecticide dispenser according to claim 1,wherein a HALS chemical is contained in at least one from the groupcomprising said inner layer, said first outer wall element and thesecond outer wall element.
 7. A laminated insecticide dispenseraccording to claim 1, wherein said inner layer comprises a furtherpesticidal agent that is able to migrate through said second outer wallelement but not through said first outer wall element.
 8. A laminatedinsecticide dispenser according to claim 1, wherein said pesticidalagent contains at least one from group consisting of an insecticide, aninsect repellant, an insect attractant, a bactericide, a fungicide.
 9. Alaminated insecticide dispenser according to claim 1, wherein saiddispenser also comprises at least one from the following substances, aninsect arrestant, a fire retarding agent, an animal repellant, asmelling agent, an ethereal oil, a medical drug, a euphoriant substance,a pain reducing substance.
 10. A method of using a laminated insecticidedispenser according to claim 1 as a direct cover for humans comprisingdispensing an insecticide only from the first surface of the dispenserfacing away from a body.
 11. A method of using a laminated insecticidedispenser according to claim 1 as a wall material for tents, comprisingforming a tent from the dispenser.
 12. A method of using a laminatedinsecticide dispenser according to claim 1 as a wall material for fieldhospitals, comprising forming a field hospital covering from thedispenser.
 13. A method of using a laminated insecticide dispenseraccording to claim 1 as a wound cover, comprising dispensing aninsecticide only from the first surface of the dispenser facing awayfrom a body.
 14. A method of using a laminated insecticide dispenseraccording to claim 1 as a collar for animals, comprising forming acollar from the dispenser.
 15. A method of using a laminated insecticidedispenser according to claim 1 as an ear tag for animals, comprisingforming an ear tag from the dispenser.
 16. A method of using a laminatedinsecticide dispenser according to claim 1 as fibre material for wovenor non-woven structures, comprising forming part of a woven or non-wovenstructure from said dispenser.